The Democratic Congressional Campaign Committee raised $13.5 million in July, surpassing past records for the month.

The committee raised $1.6 million more than it did the same month in 2016. Roughly half of the July total came from online donations, according to fundraising numbers provided first to Roll Call.

“There is no question that the grassroots are united around the goal of taking back the House,” DCCC Chairman Ben Ray Luján said in a statement. “With the unprecedented amount of Republican dark outside money, it’s more necessary than ever that Democratic candidates and our committee have the resources needed to share their stories and records of service with voters.”

Democratic candidates have also proved to be successful fundraisers themselves. In the second fundraising quarter that ended June 30, more than 50 Democratic challengers outraised their Republican incumbents, according to the DCCC.